Before Rome had all-powerful leaders, such as Caesars or Emperors, it was a republic. Under that model individuals could secure the right to be Moneyers and strike their own coins.
It’s a wonderfully diverse series with literally hundreds of different types, images, moneyers etc. A classic example however is this original Ancient Rome Silver Denarius from the first century BC.
There are varieties within this type – which way Roma’s facing, how many horses in the chariot, which way the chariot is facing, so each coin may slightly differ from the image above.